X - Y Line Tracer Gantry

Projects Discussion and Showcase Robotics
1

Hello, I am looking to make a line tracer for a servo driven metal cutting torch table. It needs to be able to follow a dark line on a light background and drive the X and Y servo motors around the tracing.

The gantry has an overhanging slide that the torch is attached too and cuts.

I have looked at the line tracer robots and this code would likely work for the tracer "eye" but wondering how I might also drive the X and Y servos to move the gantry as it follows the trace?

Anyone done this yet?

thanks!

2

If you know where the line is, you'd need to guess where to go from there, to stay on the line. One approach would be to do what a line following robot does, and move a small amount, and see where the line went. If it is not still centered below you, move a little bit, towards the line. If you move small enough distances, you can follow the line relatively accurately.

The only wrinkle is that you won't be orienting the sensor array to be perpendicular to the line, so you'll need two arrays, at right angles, and you'll need to drive the X and Y axes independently. Obviously, the center sensor will be shared by both arrays.

3

Maybe track the line with the sensor first then store the coordinates to a SD card for later use.

Then you can make as many copies as you want.

Or get into programs that can do this in a CAD environment without having to draw on the plate.

4

The easy way:

Modify the "eye", so that it emits (relative) G-Code.
Stream the G-Code to the CNC, so that the "eye" stears the CNC.

The interesting questions are:

  • What is the desired accuray?
  • How thick is the line?
  • Do you need inside/outside recognition (manual or automatic)?
  • Should it work fully automatic?

Some years ago I've built something like that for a stonemason, it used a camera+opencv :wink: